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"No Model.) I v V RrM. LOOK'WOOD & S. H.- BAR TLETT.

Transmitter for Telephones.

No. 229,153; Patented June 22,1880;

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V Witnesses- I Inventorb I mawm fizzvfiw /mz JMM/'W N. PEIERS. PHOTQ-LITKOGRAPNER. WASHINGTON. n C.

UNITED STATES A PATENT OFFIGEG ROBERT M. LOOKWOOD "AND SAMUEL H. BARTLETT, OF NEW YORK, N, Y.,

ASSIGNORS OF ONE-HALF OF THEIR RIGHT TO CHARLES F. LIVERMORE,

OF SAME PLACE.

SPECIFICATION forming part of Letters Patent No. 229,153, dated June 22, 1880.

Application filed March 9; 1880. (No model.)

To all whom it may concern:

Be it known that we, ROBERT M. LooK- woon and SAMUEL H. BARTLETT, both of the city, county, and State of New York,

have invented (:(EItitlllllGW and useful Im provements in Transmitters for Telephones or Vocal Telegraphs, of which the following is a full, clear, and exact description, reference being had to the accompanying drawing, making 10 part of this specification, which represents a side elevation, partly in section, of our improved transmitter.

Our invention relates to a novel construction of telephone-transmitter, whereby we combine mechanical vibration, so-called, in collecting or condensing the sound-waves, with what we term molecular disturbance, for the transmission of the same.

The transmitter is composed, mainly, of a block, B, of cork or other non-resonant maf ial, secured to a base-plate, A, which may of wood.

Within the block B, near its upper end, two bars, I) b, of carbon or other suitable conducting material, are firmly embedded, said bars being connected by an intervening button, as sho n. These bars are separated from the arms cl d of a magnet, D, by non-conducting plates 0 0, held in place by headed wooden pins 6 e, which pass also through the carbon plates into sockets in the ends of the arms of the magnet, connecting the latter with the carbon bars or plates.

The ends of the arms of the magnet have helices F F surrounding them in sockets formed in the cork underneath the non-conducting strips 0 0, wires from whichconnect with the carbon plates and binding or screw posts in a manner similar to that described in 4 another application filed herewith.

To the non-resonant block B, near its lower end,is secured a stud, pin, or other suitable support, 70, one or more, upon the outer end of which a board, plate, or disk, M, is secured, said plate being made, by preference, of wood, though other material may be used, the principal point being to obtain an extended surface for the sound-waves to act upon. This plate or disk stands, by preference, in a plane parallel with the adjacent face of the block B.

One of the carbon or conducting strips or bars, b, instead of terminating at the side of or within the non-resonant block, as described in another application, projects beyond the same, and the end of a spur or arm, m, attached to the inner adjacent face of plate or disk M, rests upon or in contact with this projecting end of bar b, as shown. The armor spur m is made of metal, and terminates in a narrow point or surface resting on 'the carbon, such as will offer but slight resistance to its vibration thereon.

By the organization or arrangement of parts described it will be seen that an extended surface is secured upon the plate or disk M for the sound-waves to act upon, and these are concentrated in the point or spur m and transferred to the carbon plate b by the mechanical vibration of the point thereon or otherwise, the arrangement of the support for the plate M being such, as will be seen, as to permit it to vibrate under the action of the sound-waves, said disk carrying the point or spur m with it. The vibration thus produced communicates the sound-waves, by what we term molecular disturbance, to the bar b, and thence to the button 12 lying within the completed circuit of the main-line wires, as described in another application filed herewith, and over which they are transmitted to the receiver or repeate at the other end of the circuit.

The construction of the nonresonant blockreceiver and the arrangement of the carbon plates and magnet being substantially the same, and constituting, per se, a transmitter, as described in another application, the soundwaves concentrated by the vibrating plate and point are, under the construction described, added to it, thereby greatly increasing its power; but the carbon bars and button may be used in connection with the plate M and point m; under a different arrangement and independently of or detached from the nonresonant block B, and thus made to constitute a valuable transmitter.

Having now described our invention, we claim- 1. The vibrating board or plate for the reception of the sound-waves, provided with the point vibrating in frictional contact with the mo equivalent, provided with the point or spur, as described, With the non-resonant block in which the carbon plates are cushioned or erubedded, substantially as described.

ROBT. M. LOOKWOOD. SAMUEL H. BARTLETT.

Witnesses F. L. ()URAND, ALEX. MAHON. 

